What Are We Actually Comparing?
Over the past few years, I've coordinated a lot of Allen-Bradley PLC work under brutal deadlines. In my role handling emergency orders for automation customers, I've seen two very different ways to get a machine running:
- Work through Allen-Bradley online PLC training courses, learn the fundamentals, then build a program from scratch.
- Start from a proven Allen-Bradley PLC programming example, import it, adapt it, and debug.
Both work. But they work differently. I want to compare them across four dimensions: time, depth, hardware reality, and risk. If you're here because you searched “what is vfd cable” or “control panel enclosure” while trying to save a project—this one's for you.
Dimension 1: Time to First Working Program
Online training is structured. You watch, you practice, you build. That's the right way to develop a foundation. But it isn't fast. A good Allen-Bradley online PLC training course—or rather, one that includes real exercises and Studio 5000 practice—will take you through tags, routines, tasks, and instructions. You might get a simple program running in a day or two. If you're new, plan for a few weeks.
Allen-Bradley PLC programming examples are the opposite. A documented CompactLogix or ControlLogix example program can be downloaded, opened, and studied. In an emergency, I can adapt one to a running system in hours, not days. The I/O mapping won't be perfect. Not the cleanest approach. But in a crisis, you take what works.
Clear conclusion on time: examples win.
Dimension 2: Depth of Understanding
Speed without understanding is a time bomb. Why does this matter? Because every machine fault eventually asks the question: “Why did that bit change?” If you don't know, you're guessing.
I have mixed feelings about online PLC training. On one hand, it gives you the “why” behind ladder logic, data types, tags, and instructions. On the other, it can feel painfully slow when a deadline is breathing down your neck. But when something breaks, training matters.
When I compared a team that relied on training vs. a team that only used downloaded examples, side by side on the same CompactLogix project, I finally understood why the trained team found faults faster. They knew the intended behavior. The examples team knew what the program did, but not always why it did it.
A copied example can fail in ways that don't show up during initial testing. Alias tags, UDTs, phased routines—if you don't understand them, you can't debug them. Period.
Clear conclusion on depth: online training wins.
Dimension 3: The Hardware Reality That Training Skips
Here's the part that surprised me early in my career. Most Allen-Bradley PLC issues I get called about are not logic issues. They're physical-layer issues: cable, shielding, ground, enclosure, firmware revision.
Online courses usually assume the processor is in a clean, pre-wired panel. In the field, it's never that clean.
What about “spark plug cable”?
Let's clear this up, because the search “spark plug cable” often shows up near PLC content. A spark plug cable is a high-voltage ignition cable used in engines. It is not a PLC or control cable. Putting it in a control panel is a bad idea. It's not suitable for 24V DC signals, analog inputs, or VFD circuits. I wish I had tracked how many times someone tried to save money on wire and ended up with a mysterious machine fault. What I can say anecdotally: more than once.
What is VFD cable?
VFD cable is a shielded power cable designed for variable frequency drives. It reduces electromagnetic interference from the drive's high-frequency PWM output. For an Allen-Bradley PowerFlex drive, you need the right VFD cable construction and correct shield termination. It's not the same as standard THHN. And it's definitely not spark plug wire.
Dodged a bullet when I double-checked VFD cable before a rush shipment. One click away from sending unshielded cable to a site with long drive leads. That would have been a noise nightmare.
The clearest example of prevention over cure I know is a VFD cable shield. Take 5 minutes to clamp the shield properly, and you avoid a 5-day hunt.
Control panel enclosure rating matters
Online training doesn't spend enough time on control panel enclosures. But in the real world, the enclosure is the first defense. NEMA 12 for indoor dust, NEMA 4X for washdown environments. I've seen a PLC fail because the enclosure was rated for the wrong environment. The PLC wasn't the problem. The enclosure was.
Clear conclusion on hardware: real examples win.
Dimension 4: Risk, Rework, and the 5-Minute Check
I don't have hard data on industry-wide defect rates, but based on our 200+ rush jobs, my sense is that a big share of “PLC failures” are actually wiring, cable, or enclosure problems. Not the processor.
That's why my team now runs a checklist before anything is declared ready:
- Controller and firmware revision are compatible with the Studio 5000 version you're using.
- I/O wiring and module addressing match the program tags.
- VFD cable is the correct type and is shielded/terminated per the drive manual.
- Control panel enclosure rating matches the environment.
- No electrical tape where a proper terminal block should be. Happens more than you'd think.
This isn't glamorous. It's just cheaper. 5 minutes of verification beats 5 days of correction. That's it.
(Should mention: the checklist only works if you actually follow it.)
So: Online Training or Programming Examples?
Bottom line: it depends on the situation.
- If you're new to Allen-Bradley PLCs and will support this machine for years, invest in Allen-Bradley online PLC training first. Build the foundation.
- If the machine is down and the shift starts in six hours, get a working Allen-Bradley PLC programming example and start adapting it now.
- Whatever path you take, verify the physical layer before you trust the logic. That means cable types, VFD cable, shields, and the control panel enclosure.
This is based on what I've seen through early 2025. Rockwell Automation updates Studio 5000 versions and controller firmware often, so verify compatibility at the Product Compatibility and Download Center before you start. Things change fast.
If your answer to “why did that bit change?” is “I don't know,” you need more training. If your answer to “can we have a working program by Friday?” is “let me go take a course,” find an example. Fast.
